1. Field of the Invention
The present invention relates to a technique for recording content data, such as video data, on an optical information recording medium, such as a DVD-R (Digital Versatile Disk-Recordable) or a DVD-RAM.
2. Description of Related Art
As a data compression technique for moving picture images, the MPEG (Moving Picture Image Coding Expert Group) system is well known. Moreover, the DVD video is well known as an optical disk that contains video data compressed by the MPEG2 data compression technique and navigation data showing the reproduction method of the video data. The logical format and the reproduction method of the DVD video are described in detail in Japanese Patent Application Laid-Open No. Hei 8-273304. These items have been selected to formulate the DVD Video Standard.
More specifically, data on DVD video is formed in volume and file structures, and the formats of volume and file structures are prescribed in Micro UDF (Universal Disk Format) and ISO (International Standard Organization) 9660. Information about the format of the volume and file structure (volume data, file structure data) is described in the management area provided in Micro UDF and ISO 9660.
The DVD-R is interoperable with the DVD video and is a write once read many type optical disk into which the user can record information. Detailed description about the DVD-R is given, for example, in xe2x80x9cDVD-R: Recordable by the Userxe2x80x9d in Denshi Gijutsu (Electronics Technology), August, 1996 pp. 10-14.
According to the literature mentioned above, the DVD-R have the same logical format as that of the DVD video, and therefore information can be reproduced from a DVD-R in the same manner as with a DVD video disk. However, when a user records video data in a DVD-R, as shown in FIG. 19, he transfers video data, which is to be recorded on a DVD-R 109, from his video camera 101 or the like into a VTR 102. The video data sent to the VTR 102 is compressed by an MPEG encoder 103, and recorded as material data in memory 104. Then, a DVD authoring system 105 is used to edit the video data to generate a file of the same format as that of logical data in conformity with the DVD Video Standard, the file is temporarily recorded in a large-capacity intermediate medium 106, such as a tape device. After all necessary files are complete, a DVD formatter 107 is used to convert those files into the physical format in conformity with the DVD Video Standard, and the files are recorded in a DVD-R 109 by a cutting machine 108 as a recording device.
As has been described, in the conventional DVD-R, it is necessary to generate a file of the logical data format in conformity with the DVD Video Standard, temporarily record in a large-capacity intermediate medium, such as a tape device, then covert those files into the physical format in conformity with the DVD Video Standard, and record the files on a DVD-R. Therefore, the recording data requires at least twice as long as reproducing recorded data.
Description will be given of the reasons why the above-mentioned steps are required.
A data unit to be reproduced includes data pack strings each of which are obtained by compressing according to the MPEG format, content data including at least any of an audio signal, a main video signal and a sub picture signal, and dividing the content data into packets. The data unit further includes a navigation pack, which is placed at the head of the data pack string and contains reproduction information about the data pack string and navigation information describing the relation of the data unit with other data units. The content data is reproduced on the basis of navigation information.
A set of data units mentioned above is called a data cell. Data cells are reproduced successively in time series. Cell reproduction information concerning reproduction of data cells is written in a table outside data cells and is referred to at playback as navigation data.
A video stream includes at least one set of data cells and is called a video object (VOB). One or more video objects that have a common attribute is called a video object set (VOBS). Therefore, in an ordinary movie with one story, one video object corresponds to one video object set, and one video stream concludes with one video object set. Video title set information (VTSI), which describes information for use in reproducing a video object set and attribute information, and a backup of video title set information (VTSI_BUP) are respectively arranged before and after the video object set, and those items of information constitute a video title set (VTS).
A maximum of 99 video title sets can be placed on a DVD-R, and a video manager (VMG) that describes information for managing the video title sets is arranged just before a group of video title sets.
As is understood from the foregoing, video title set information (VTSI) as navigation data for a video object set is undetermined until the end of recording of a video object set. A video manager for managing the respective video title sets is undetermined until recording of all video title sets is finished. Volume and file structure data for managing the contents on the disk as files and directories is undetermined until all data are recorded on the disk are determined.
On the contrary, according to the DVD Video Standard, the video manager, the volume and file structure data are recorded in the leading portion (more specifically, the inner circumference portion) of a recordable user area on the disk. For this reason, when video data is recorded on a DVD-R, as shown in FIG. 19, from compressed data to be recorded, files are generated in the logical data format in conformity with the DVD Video Standard, and are temporarily recorded in a large-capacity intermediate medium 106, such as a tape device. After all files are complete, in other words, after it has become possible to determine a video manager and volume and file structure data, it is necessary for the DVD formatter 107 to perform sectoring and modulation according to the physical format in conformity with the DVD Video Standard, and the cutting machine 108 sequentially records data starting from the inner circumference portion of the DVD-R 109.
As described above, until all video title sets to be recorded on the DVD-R are determined, a video manager is not determined and cannot be recorded. A DVD-R without a video manager recorded thereon cannot be played on the DVD video reproducing device. Therefore, with a current DVD-R, it is impossible to record TV programs or commemorative pictures and reproduce them immediately afterwards as we do with a video tape recorder (VTR) or a video-movie.
The present invention has been made with the above problem in mind and has as its object to enable the pictures taken with a video camera to be directly recorded on an optical recording medium (optical disk), such as a DVD-R in a format reproducible on a DVD video reproducing device without using an intermediate medium. Another object is to enable a scene to be recorded in such a way that discontinuity does not occur when it is reproduced.
To solve the above problem, according to the present invention, there is provided a DVD recorder for recording content data including any of input main video signal, sub picture signal, and audio signal on an optical information recording medium in a recording format in conformity with the DVD Video Standard, the DVD recorder comprising:
data compression means for compressing the content data at a fixed data compression rate;
data formatting means for adding reproduction information for the content data and navigation data showing the relation with other content data to the content data compressed by the data compression means, and converting the content data into a format in conformity with the DVD Video Standard;
data recording means for recording on an optical information recording medium the content data converted into a format in conformity with the DVD Video Standard by the data formatting means; and
control means for centrally controlling the respective means, wherein the control means includes:
reserved area securing instruction means for instructing the data recording means to secure a reserved area having a predetermined capacity on the optical information recording medium;
video title set recording instruction means for instructing the data formatting means to convert the content data compressed by the data compression means into at least one video title set, including a video object set and video title set information describing information for reproducing the video object set and describing attributes information, and also for instructing the data recording means to sequentially record at least one video title set, obtained by the conversion, in the area following the reserved area on the optical information recording medium;
video manager recording instruction means for instructing the data formatting means to generate a video manager for managing the video title sets recorded on the optical information recording medium in accordance with the DVD Video Standard, and also for instructing the data recording means to record the video manager in the rear portion of the reserved area after the video title sets have been recorded on the optical information recording medium as instructed by the video title set recording instruction means; and
volume and file structure data recording instruction means for instructing the data formatting means to generate volume and file structure data as information for managing contents on the optical information recording medium as files and directories in accordance with the DVD Video Standard, and also for instructing the data recording means to record the volume and file structure data in a front portion of the reserved area after the video manager has been recorded on the optical information recording medium as instructed by the video manager recording instruction means.
According to the present invention, a reserved area is previously secured on an optical information recording medium, content data compressed at a fixed compression rate is converted into at least one video title set in accordance with the DVD Video Standard, and the video title sets obtained by the conversion are sequentially recorded in the area following the reserved area. After the end of recording, lead-out data is recorded in a lead-out area, a video manager is recorded in the rear portion of the reserved area, and volume and file structure data is recorded in the front portion of the reserved area. Finally, lead-in data is recorded in the lead-in area.
By recording as mentioned above, it becomes possible to directly record a video title set on an optical information recording medium before a video manager and volume and file structure data are determined. Therefore, according to the present invention, pictures taken by a video camera can be recorded directly on an optical information recording medium, such as a DVD-R, in a format in conformity with the DVD Video Standard without using an intermediate medium.
Meanwhile, in the present invention, the above-mentioned video title set recording instruction means may be configured to instruct the data formatting means to convert the content data compressed by the data compression means into at least one video title set having a predetermined capacity, and also instruct the data recording means to sequentially record at least one video title set, obtained by the conversion, in the area following the reserved area on the optical information recording medium. In this case, the video title set recording instruction means preferably instructs the data recording means to record content data in one video title set as a single data cell.
With the above arrangement, it becomes possible to determine video title set information before a video object set is recorded, so that video title set information and a video object set can be recorded in this order on the optical information recording medium, and thus a video title set is recorded.
In the present invention, the video title set recording instruction means may include video title set information area securing means for instructing the data recording means to secure a video title set information reserved area of a predetermined capacity in the front portion of each video title set area when a video title set is recorded; data cell recording means for instructing the data recording means to record at least one data cell of a predetermined capacity in the area following the video title set information reserved area; and video title set information recording means for instructing the data recording means to record video title set information in the video title set information reserved area after data cells have been recorded on the optical information recording medium by the data cell recording means. In this case, the video title set recording instruction means preferably instructs the data recording means to record a video title set with a plurality of data cells, each having a predetermined capacity, included in it.
With this arrangement, it is possible to start recording on an optical information recording medium a video object set corresponding to a video title set information before the video title set information is determined. Because a video title set of any desired length can be used, one scene can be accommodated in one video title set. Therefore, one scene can be recorded in such a way that the scene does not discontinue at playback.
In the present invention, the control means may further comprise:
lead-out data recording instruction means for instructing the data formatting means to generate lead-out data in accordance with the DVD Video Standard, and also for instructing the data recording means to record the lead-out data in a lead-out area following the recorded area of the video title set on the optical information recording medium after video title sets have been recorded on the optical information recording medium by the video title set recording instruction means and before the video manager recording means starts recording a video manager on the optical information recording medium;
zero data recording instruction means for instructing the data formatting means and the data recording means to record zero data between the front portion of the reserved area on the optical information recording medium where the volume and file structure data was recorded and the rear portion of the reserved area where the video manager was recorded after volume and file structure data has been recorded on the optical information recording medium as instructed by the volume and file structure data recording instruction means; and
lead-in data recording instruction means for instructing the data formatting means to generate lead-in data in accordance with the DVD Video Standard, and also for instructing the data recording means to record the lead-in data in the lead-in area on the optical information recording medium after zero data has been recorded on the optical information recording medium by the zero data recording instruction means.
In this case, the control means may further include:
program memory area securing means to instruct the data recording means to secure a program memory area at a location further in than the lead-in area or at a location further out than the lead-out area;
information recording instruction means for instructing the data recording means to record information concerning the video title set in the program memory area each time a video title set has been recorded; and
data generating instruction means for instructing the data formatting means to generate the volume and file structure data and the lead-in data by referring to information recorded in the program memory area after the final video title set has been recorded.